As the Texas Longhorns begin their journey towards the 2007 season on Friday with the beginning of spring workouts, much of the team's attention will be placed on a defensive unit that has two injured starting defensive tackles, is trying to replace both starting ends and three of the four starters in the secondary, and upgrade at all three linebacker spots at the same time.

The good news for the Longhorns is that the cupboard is far from being emptied, especially after the coaching staff brought in two of the best recruiting classes in Mack Brown's tenure at Texas. In fact, a case can be made that the Longhorns have more standout young defensive players coming up through the ranks than at any other time in recent memory.

Here's a look at five of those young players that could shake things up this spring:

Lamaar Houston - The 6-2, 265-pound sophomore from Arizona is one of the few recent out of state imports that the Longhorns have brought into the program in recent years, but he has a chance to be as good as anyone Texas has signed up-front on the defensive line in recent years. The former high school running back has an incredible combination of size and athleticism, and with the Longhorns looking to replace Brian Robison and Tim Crowder, Houston is expected to battle Aaron Lewis, Eddie Jones and Brian Ellis in the spot opposite of Brian Orakpo (one of the two expected starters). Lewis has the edge on Houston in experience and he's been a very solid role player, but Houston is the most talented athlete of the group.

Roddrick Muckelroy - Mack Brown has said on several occasions that the loss of Muckelroy from last year's defense was a much bigger blow to the unit than most realize. Although the 6-2, 230-pound sophomore has only played a handful of snaps in his career, the staff feels like he's the best linebacker on the team. With three returning starters returning from 2006, Muckelroy is expected to replace someone in the starting line-up. It's up to Scott Derry, Robert Killebrew and Rashad Bobino to raise their performance levels, so that it's not them. However, someone is likely to lose their job, which is why the competition at linebacker is so compelling.

Sergio Kindle - While many feel like Muckelroy is the best linebacker on the team at this very moment, nobody has as much upside as Kindle, who battled injuries and adjusting to a new level of competition as a true freshman. It might be premature to say that Kindle is ready to be a starter right now because he's yet to prove that he's ready for that responsibility, but everyone in the program (especially the players) thinks that this kid is headed for a superstar career whenever the light switch finally turns on. If it happens this spring under the tutelage of Larry Mac Duff, someone else in that linebacker group will likely lose a starting job.

Chykie Brown - Of all of the players that opened up some eyes during Alamo Bowl workouts, the performance of the redshirt freshman from Galena Park North Shore might have been the most impressive, especially of those playing in the secondary. At 6-1, 180 pounds, Brown has already shown great ball skills and the ability to quickly break on the ball. Now they want to see some consistency. Word on the street is that Duane Akina thinks this kid has a chance to be as good as anyone the Longhorns have had in the secondary. Obviously, that's praise of the highest order.

Robert Joseph - Before he was injured during the Baylor game, this sophomore from Port Arthur was very quickly emerging as a force at safety and his playing time was certainly on the rise. With every spot in the secondary open for competition this spring, Joseph has a chance to push himself into a starting spot if he can take his play forward and build off of what he showed as a true freshman. With his range and ball skills, Joseph is a guy that has a chance to be a star at this level. He simply needs to stay healthy and become more consistent.